Fatty amine salts of acid phosphate di-esters



Patented July 9, 1946 UNITED STATES FATTY-AMINE SALTS. .OF ACID PHOSPHATE DI-ESTEBS Herschel G. Smith, Wallingford, and Troy L.- Cantrell, Lansdowne, Pa., assignors to Gulf Oil Corporation, Pennsylvania Pittsburgh, Pa., a corporation of No Drawing. Application March 19, 1945,

" Serial No. 583,652

" 19 Claims.

This invention relates to fatty amine salts of a acid phosphate di-esters, and it comprises Coilsoluble, substantially neutral addition products of primary fatty amines and'acid phosphate di-' esters of alkylated phenols; said neutral addition products being useful as rust preventive compounds 'or rust inhibitors; and it further comprises methods of jmaking said neutral addition products wherein the said acid phosphates and primaryfatty amines containing from 8*to 18 carbon'atoms are chemicallyv combined together, in approximately equimolecular ratios, to produce substantially neutral addition products having-a pH between 5.5 and 7.5, said addition products orgaminesalts being readily soluble in and miscible with hydrocarbons, such as volatile hydrocarbon solvents, mineral oils, waxes and the like; all as more fully hereinafter described: and

claimed.

This application'is a continuationdn-partx-of our prior copending application serial No. 504,057, filed September 27, 1943. In-our prior application, wehave described improved anti-rust petroleum lubricants and mineral oil compositions containing minor amountsof thesubstantially neutral addition products of primary fatty amines and acid phosphate di-esters of-alkylated phenols, as rust inhibitors or rust preventive compounds. The present application is directed to such-rust inhibitors or rust preventivecompounds, per se.

That the present invention relates to new oil-soluble, substantially neutral addition salts of primary fatty amines and acid phosphate diesters of alkylated phenols. Generically, these fatty amine salts may be represented by the following formula:

R-NHa wherein R represents an alkyl group containing from 8 to 18 carbon' atoms, and R, R." and-R" represent hydrogen or an alkyl group, at least one branched chain alkyl group being present.

As a class, the above amine salts are relatively non-volatile, even at elevated temperatures. Most of them are oily, viscous liquids at room temperatures. Others are soft, waxy solids which melt to oily liquids at slightly elevated temperatures. All of them are insoluble in water and aqueous liquids and are resistant to hydrolysis. Indeed, these oily and waxy amine salts are quite water-repellent. Also, they are'relatively' stable 2 compounds. For instance, they can be heated to elevated temperatures as stated ante, and this is frequently done in incorporating them in waxes, petrolatum and mineral oils. However, if heated to excessive temperatures, say 260 F. orabove, for long periods, they become converted into corresponding amide compounds, water being split 01f at such higher temperatures. Generically, our'new amine salts are readily soluble in oils, both mineral oils and fatty oils. Of course, their solubility varies somewhat with a particular oil and amine salt,but is quite high in general. Further, in addition tobeing readily soluble in mineral oils, they are readily miscible with other hydrocarbons, such as petrolatums, Waxes and volatile hydrocarbon liquids, and coating compositions containing the same; they being readily solublein hydrocarbonliquids, particularly volatile hydrocarbon solvents. When incorporated in hydrocarbons, such as mineral oils and the like, they impart marked anti-rust qualities thereto, as shown in our prior application Serial No.,.504,05'7. In other words, as described andillustratedin that application, our new primary fatty amine salts'are excellent rust preventive compounds or rust inhibitors.

.These advantageous rust inhibitors can be readily prepared from primary fatty amines containingfrom 8 to 18carbon atoms and acid-phosphate esters of alkylated phenols containing at least one branched chain alkyl group,-by reacting said amines and acid phosphate esters together in approximately equimolecular ratios, as stated ante. In preparing our rust inhibitors'or reaction products, the reaction is controlled so as .to produce substantially -neutral reaction products or mixtures having a pI-I'value within therange 5.5 to '75 (as measured with quinhydrone-calomel electrode assembly). The primary fatty amines employed as one reactant are mono-alkyl amines having the following formula:

terials. This advantageous xclass of. primary fatty amines may be represented by the following formula:

wherein n is an even number between 6 and 16. This generic class includes the following members:

Mono-capryl amine, CH3(CH2) sCHzNI-Iz Mono-lauryl amine, CH3(CH2)10CH2NH2 Mono-myristyl amine, CH3(CH2)12CH2NH2 Mono-palmityl amine, CH3(CH2)14CH2NH2 Mono-stearyl amine, CH3(CH2)15CH2NH2 Any of the above amines yield advantageous rust inhibitors when reacted with the said acid phosphate esters as described ante.

That is, we sometimes prepare the rust inhibitors by reacting the acid phosphate esters with some particular one of these amines, but more usually mixtures of fatty amines of this group are employed as they afford a somewhat better product than if only one amine is used; One commercially available mixture, which we ordinarily employ, is the so-called coco amine made in known ways by conversion of cocoanut oil fatty acids into corresponding amines. Coco amine contains a major amount of mono-lauryl amine (the C12 amine) with minor amounts of its adjacent homologues. The average molecular weight of cocoamine ranges between 200 and 210. A value within this range is considered as the molar weight in reacting cocoamine-with the acid phosphate ester.

The other reactant, the acid phosphate esters,

are di-esters of ortho phosphoric acid and may be represented by the following generic formula:

RI RI 7 a O R!!! l R!!! wherein R, R and R' represent hydrogen or an alkyl group, at least one branched chain alkyl group being present.

These acid phosphate esters can be prepared by various methods from alkylated phenols containing one or more branched chain alkyl groups attached to the phenyl nucleus in the positions indicated ante.

In particular, the acid phosphate di-esters of 4-tertiary-butyl phenol, Z-tertiary-butyll-secondary butyl phenol, ZA-ditertiary-butyl phenol, 2,6-ditertiary-butyl 4 secondary-butyl phenol, 2,4,6-tritertiary butyl phenol, 2,6-ditertiarybutyl-l-methyl phenol and 4,6-ditertiary-butyl- 2-methyl phenol are advantageous for the present purposes. For instance, as shown in the illustrative examples post, di-(2,4,6-tritertiary-butylphenyl) phosphate and di-(2,4-ditertiary-butylphenyl) phosphate are advantageousin preparing our rust inhibitors. These new acid phosphate di-esters are viscous oily liquids at room 7 temperature and are readily soluble in mineral oils. Accordingly mineral oil solutions of these acid phosphate esters may be employed in preparing concentrates of our rust inhibitors in oil; the amine being added to such oil solutions and reacted with the acid phosphate esters dissolved therein to form the rust inhibitor in'situ in the oil. In general, acid phosphate di-esters of alkylated phenols containing tertiary or secondary alkyl groups are useful and advantageous in preparing our rust inhibitors; those containing a plurality of such tertiary or seeondary alkyl groups being particularly advantageous for the present purposes. Such acid phosphate di-esters are readily soluble in mineral oils and have other properties rendering them advantageous for the purposes of this invention.

As a class, these acid phosphate-di-esters of alkylated phenols containing branched chain alkyl groups react readily with primary fatty amines. In general, the reaction is exothermic and is quite vigorous in most cases. In preparing our rust inhibitors, the reaction temperature is controlled by suitable means to secure smooth reaction and obtain addition products of the amine and acid phosphate esters. In doing so, the temperature of the reaction mixture i controlled by cooling or heating as required; the temperature of the reaction mixture being maintained below 180 F., to avoid splitting out water from the mixture. Ifhe reaction temperature is usually maintained between and F. during the larger portion of the reaction and within this range excellent rust inhibitors are obtained; the pH value of the-reaction products being adjusted in the final stages f the reaction to within the desired range stated ante.

The following examples illustrate advantageous methods of preparing these rust inhibitors:

Example I.--Into a suitable kettle, equipped with means for heating, cooling and agitating the charge, there were added 4'74 pounds of di-(2,4-ditertiary-butyl-phenyl) phosphate, and then 185 pounds of primary dodecyl amine (mono-lauryl amine) were gradually added with stirring. The reaction was vigorous and exothermic, and the amine was added at such a gradual rate as to facilitate maintaining the reaction temperature below F.; the mixture being cooled if necessary to maintain it below that temperature. In this way, the reaction temperature was maintained between 140 and 170 F. during the larger part of the reaction. By so controlling the temperature, the side reactions are checked, particularly the splitting out of water from the addition product and conversion of it into the corresponding amide.

After the exothermic reaction had subsided, a further 18 pounds of dodecyl amine were added to the warm reaction mixture and this mixture stirred until the reaction was complete.

The substantially neutral addition product so obtained was a heavy viscous, oily liquid when cooled to room temperature. It had a pH value of approximately 6.8. This amine salt or rust inhibitor had a pleasant odor and a light amber red color. It was soluble in mineral oils and other hydrocarbons. It is an excellent rust inhibitor for the present purposes.

Similar viscous, oily rust inhibitors can be readily obtained, having pH values within the range of 5.5 and 7.5 by the method described ante. For instance, our oily rust inhibitors can also be prepared from other primary fatty amines and other acid phosphate di-esters of alkyl phenols, as well as from the particular amine and acid phosphate ester employed in Example I. The preparation of another such advantageous rust inhibitor is illustrated in the following example.

Example II.Here again, the reaction is carried out in a suitable kettle, equipped with means for heating, cooling and agitating the mixture, and the reaction temperature is controlled as described in Example I ante.

Into such a kettle, there were introduced 474 pounds of di-(Z-tertiary butyll-secondary butyl phenyl) phosphatauand then 185.330unds2oiprimary dodecyl amine weregradual-lyaddedwith stirring. Thereaction was. vigorous and quite exothermic and the amine was added at sucha gradual rate as to maintain the reaction temperature below 180 F.; the temperature-being maintained between 140and 1'70'F.-;' as described inExample I. V i

After the exothermic reaction had subsided,-a further 20 pounds ofdodecyl amine" were added to 'the warm reaction mixture and this mixture stirred-until the reaction was complete The dodecyl amine salt so obtained was a viscous; oily'liquid at roomtemperature- It; had a pleasant odor and a light amber red color." It was soluble in mineral oils and othe'rhydrocarbons; Thus, this rust inhibitor is advantageous in making :our improved oil compositions;

The above rust inhibitor or amine salt maybe represented by the followingformula:

H31 TCHz- -(CH2) CH3 v V This dodecyl amine mlt had apH- value of approximately 7.2; it being a substantiallyneutral addition product of said amine-and said acid phosphate di-ester, as shown-by the above for-- mula.

Example III.--Into a suitable kettle (suchas used in Example I) there were added 185 poundsof dodecyl amine; and then 586 pounds of di(2,4,6-tritertiary butyl phenyl) 1 phosphate were gradually added withstirring. .The reaction was vigorous and quite exothermic, and the acid phosphate was added at such a gradual rate as to facilitate maintaining the reaction temperature below 180 F., the mixture being cooled if desired to maintain it below that temperature.

After the exothermic reaction had subsided, a further 18 pounds of dodecyl amine were added to the warm reaction mixture and this mixture stirred until the reaction was complete.

The rust inhibitor so obtained was a viscous, oily liquid at room temperature. It had a light amber red color and a pleasant odor. It was soluble in mineral oils and like hydrocarbons.

In other words, the substantially neutral reaction products obtained in Examples I to III, respectively, like the' amines and acid phosphate esters from which they were prepared, are soluble in mineral oils. Accordingly, we sometimes prepare concentrated solutions of these rust inhibitors in mineral oil by forming them in situ in the oil. In such processes, the primary fatty amine is first dissolved in the mineral oil and then the acid phosphate ester added, the mixture being stirred and maintained at the desired temperature until the reaction is complete and the mixture has a pH value within the specified range. In preparing such oil concentrates of our rust inhibitors, sometimes additional amine is added in the later stages to adjust the pH value as desired. The concentrates or oil solutions of inhibitor reaction products so obtained are useful addition agents to various types of lubricants. The preparation of such concentrates is illustrated in the following example. 7

Example IV.Into a suitable kettle, equipped with means for heating, cooling and agitating the charge, there were charged 817 pounds .of

were gradually added to the solution of saidaminein the oil, over a period-oftwo hours; the temperature of the reaction mixture being approximately 178 F; when all the amine had been added; Then the reaction mixture was maintained at said temperature for an additional hour. Finally, a further 21 pounds of dodecyl amine were added to the warm mixture and, the resultant mixture stirred until the reaction was complete, and the oil solution of addition. productsso obtained had a pH of 7.2." e

The oily mixture prepared in this Example I can be regarded as a sort of concentrated stock solution which can be stored indefinitely and incorporated in lubricating oil as desired to prepare commercial anti-rust oils, etc.

In general, the rust inhibitorsor reaction products prepared as described ante, may be dissolved in various types of mineral oils and improved anti-rust and non-corrosive oil compositions obtained whichare capable of inhibiting or retarding the rusting or corrosion of various metals as described.

What we claim is:

1. As new compositions of matter, useful as rust preventive compounds and for other purposes-, the oil-soluble addition salts having the following formula:

. R!!! I I I RNH3 wherein R represents an alkyl group containing from 8 to 18 carbon atoms, and R, R", and R represent a substituent selected from the class consisting of hydrogen and an alkyl group, at least one branched chain alkyl group being present, said amine salt being a substantially neutral compound soluble in mineral oils and miscible with hydrocarbons.

2. The composition of claim 1 wherein said addition salt is a salt of primary dodecyl amine.

3. The composition of claim 1 wherein said addition salt is a salt of cocoamine.

4. As new compositions of matter, the oil-soluble addition salts of primary fatty amine containing 8 to 18 carbon atoms and acid phosphate di-esters of 2,4,6-trialkylated phenols containing at least one branched chain alkyl group, said primary fatty amine salts being substantially neutral compounds soluble in mineral oils and miscible with hydrocarbons.

5. The composition of claim 4 wherein said addition salt is the primary dodecyl amine salt of di-(2,4,6-tritertiary-buty1-phenyl) phosphate.

6. As new compositions of matter, the oil-soluble addition salts of primary fatty amines containing 8 to 18 carbon atoms and acid phosphate di-esters of 2,4-di-alkylated phenols containing at least one branched chain alkyl group, said primary fatty amine salts being substantially neutral compounds soluble in mineral oils and 8. The composition of claims'fi wherein said addition salt is a primary dodecyl amine salt of di-(2-tertiary-butyl-4-secondary butyl-phenyl) phosphate.

9. The composition of claim 6 wherein said addition salt is the cocoamine salt of di-(2,4-ditertiary-butyl-phenyl) phosphate.

10. A new compositions of matter, the oil-soluble addition salts of primary fatty amine containing 8 to 18 carbon atoms and acid phosphate di-esters of mono-alkylated phenols containing at least one branched chain alkyl group, said primary fatty amine salts being substantially neutral compounds soluble in mineral oils and miscible with hydrocarbons.

11. The composition of claim 1 wherein said addition salt is a substantially neutral amine addition salt of a primary fatty aminehaving the following formula:

wherein n is a number between 6 and 16.

12. As an improvement in the manufacture of oil-soluble, rust preventive compounds from acid phosphate di-esters of alkyl phenols having the following formula:

O R!!! I RI]! temperature below 200 F.,'to produce'substantially neutral addition products thereof.

13. The process of claim 12 wherein the reactionis effected at temperatures between and 200 F.

14. As an improvement in the manufacture of oil-soluble, rust preventive compounds, the improved process which comprises reacting rimary fatty amines containing 8 to 18 carbon atoms with acid phosphate di-esters of 2,4,6-tri-alkylated phenols containing at least one branched chain alkyl group, at temperatures between 140 and 200 F., the said amine and acid phosphate ester being reacted and combined in substantially equimolecular proportions to form substantially neutral addition products thereof.

15. The process of claim 14 wherein said acid phosphate di-ester is di-(2,4,6-tri-tertiary-butylphenyl) phosphate.

16. As an improvement in the manufacture of oil-soluble, rust preventive compounds, the improved process which comprises reacting primary fatty amines containing 8 to 18 carbon atoms with acid phosphate di-esters of 2,4-di-alkylated phenols containing at least one branched chain alkyl group, at temperatures between 140 and 200 F., the said amine and acid phosphate ester being reacted and combined in substantially equimolecular proportions to form substantially neutral addition products thereof.

17. The process of claim 16 wherein said acid phosphate di-ester is di-(2,4-di-tertiary-butyl phenyl) phosphate.

18. The process of claim 16 wherein said acid phosphate di-ester is di-(2-tertiary-buty1-4 secondary butyl-phenyl) phosphate. 7

19. The process of claim 16 wherein said fatty amine is primary dodecyl amine.

' HERSCHEL G. SMITH.

TROY L. CANTRELL. 

